Subtracting Without Borrowing
Subtraction without borrowing is slightly harder than simply subtracting one digit numbers, as the previous section showed, but it is similar in the sense that you are still going to be subtracting one digit numbers, you'll just be doing it more than once for the same problem. The problems will be lined up in columns, so you would subtract the column on the right first and then work your way to the left. Examples are shown below:
Subtracting Two Digit Minus One Digit Numbers
As you get better with subtraction, you’ll be asked to subtract one digit numbers from two digit numbers. For example, a two digit minus one digit number subtraction problem may look like this:
One of the most important things to remember about subtraction with more than one digit is that you have to keep your place values lined up. In our problem above, the ones’ columns are aligned at the right. This is very important. After you make sure the columns are lined up, all you have to do is subtract by column, from right to left. When you’re ready to start subtraction, make sure you start with the ones’ column, or the column furthest to the right. We have this circled in red in our example below:
When we subtract the ones column, 6 – 4, we get 2 as our answer, so we write it in the ones’ column beneath the answer bar. Next, we have to subtract the tens’ column. In this example, there is only one digit in the tens’ column, so we simply bring it down into our answer, as shown by the red arrow in the example below.
Thus, 12 is our final answer.
Let’s try another example. This time, we’ll let you try working it out, and then you can compare your answer with ours. Here’s the problem:
Now, try it on your own. When you’re done, compare it to our answer.
Does your answer agree with ours? If not, go back and re-subtract the ones column. Then make sure you brought down the tens’ column, since there was not another number to subtract. If you did get 42, congrats! You did it correctly!
Subtracting Two Digit Minus Two Digit Numbers
The next step in subtraction is taking two digit numbers and subtracting other two digit numbers. A two digit minus two digit number subtraction problem would look like this:
The most important thing you need to remember in doing a problem like this is that you always start with the ones’ column (or the column furthest to the right) and work your way to the left of the problem. This may seem wrong, because normally we do things from left to right, not from right to left. However, when doing subtraction, we always want to start at the right and work towards the left.
The first part of the problem, starting with the ones’ column, looks like this:
Notice the ones’ column is circled, because we started with it. Now, let’s look at the second step in solving the problem:
Thus, our final answer is 55.
Let’s try that one more time to make sure you understand. Your new problem is:
Now, following the same pattern as above, see if you can work through this one on your own, and then check your answer with ours.
Thus, our final answer is 53.